﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using app.Models;
using System.Drawing;
using System.Text;

namespace app.Api
{
	public class codevalidate
    {
        public static string GenerateCheckCode()
        {
            //利用random()随机产生四位大写的字符串（包含数字和字母）
            int number;
            char code;
            string checkCode = string.Empty;
            Random random = new Random();
            for (int i = 0; i < 4; i++)
            {
                number = random.Next();
                //下面也可以用其他的方法构思
                if (number % 2 == 0)
                    code = (char)('0' + (char)(number % 10));
                else
                    code = (char)('A' + (char)(number % 26));
                checkCode += code.ToString();
            }
            return checkCode;
        }
        public static string CreateCheckCodeImage(string checkCode)
        {
            //该函数主要是画背景色的       
            if (checkCode == null || checkCode.Trim() == string.Empty)
                return null;
            System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
            Graphics g = Graphics.FromImage(image);
            try
            {
                //生成随机生成器
                Random random = new Random();
                //清空背景色
                g.Clear(Color.White);
                //画背景的噪音线
                for (int i = 0; i < 2; i++)
                {
                    int x1 = random.Next(image.Width);
                    int x2 = random.Next(image.Width);
                    int y1 = random.Next(image.Height);
                    int y2 = random.Next(image.Height);
                    g.DrawLine(new Pen(Color.Black), x1, y1, x2, y2);
                }
                Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold));
                System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(60, 60, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
                g.DrawString(checkCode, font, brush, 2, 2);
                //画图片的前景噪音点
                for (int i = 0; i < 100; i++)
                {
                    int x = random.Next(image.Width);
                    int y = random.Next(image.Height);
                    image.SetPixel(x, y, Color.FromArgb(random.Next()));
                }
                //画图片的边框线
                g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
                string title = "data:image/jpeg;base64,";
                string img = Convert.ToBase64String(ms.ToArray());
                return title+img;
                //Response.ClearContent();
                //Response.ContentType = "image/Gif";
                //Response.BinaryWrite(ms.ToArray());
            }
            finally
            {
                g.Dispose();
                image.Dispose();
            }
        }
    }
}